Control method of cooling fan, and information processing device

TECHNICAL FIELD

The present invention relates to the cooling of an information processing device, and particularly, relates to the control of a cooling fan in the information processing device to which an external memory device, etc. can be detachably attached.

BACKGROUND OF THE INVENTION

A microprocessor such as a central processing unit, etc., arranged in an information processing device generates heat during its operation. A cooling fan is arranged in the information processing device to prevent an operation error due to this heat, an influence of this heat on lifetime, etc.

Since, however, the cooling fan generates noises depending upon a rotation speed, it is desirable to set the rotation speed of the cooling fan to a necessary minimum limit. There is therefore known a technique for arranging a temperature sensor near the central processing unit, and adjusting the rotation speed of the cooling fan on the basis of a temperature near the central processing unit.

In recent years, compactness of the information processing device is advanced, and an external memory device, a memory medium reader, etc., which are conventionally often designed as a built-in fixing type, are designed as an attaching-detaching type for further improving portability, etc. or coping with the diversity of a use mode of a user, etc. In this case, it is considered desirable to permit internal mounting of the “external” memory device, memory medium reader, etc., instead of their external mounting in view of usability at a mounting time, outer appearance, etc.

DISCLOSURE OF THE INVENTION

However, when the “external” memory device of the attaching-detaching type, etc. are internally mountable, the external memory device, etc. themselves constitute new heat sources within the information processing device during the mounting, and are objects to be cooled. Further, it is considered that the paths of cooling air currents are changed depending upon whether they are mounted or not mounted. Therefore, no sufficient cooling effects may possibly be obtained in the cooling fan control similar to that during non-mounting time.

An object of the present invention is to provide an information processing device that permits internal mounting of an “external” memory device, etc., in which suitable control of the cooling fan is performed depending upon an attaching-detaching state of the external memory device, etc.

For overcoming the above problems, the present invention provides a method of controlling a cooling fan in an information processing device that permits internal mounting of a relevant device, comprising the stages of:

obtaining an internal temperature of the information processing device;

obtaining an attaching-detaching state of the relevant device;

obtaining a value relative to a rotation speed of the cooling fan which rotation speed corresponds to the obtained temperature, by referring to data which shows the relationship between the value relative to the rotation speed of the cooling fan and the temperature, and is determined depending upon the attaching-detaching state of the relevant device; and

controlling the rotation speed of the cooling fan on the basis of the value relative to the rotation speed of the cooling fan.

The above relevant device refers to an external memory device, a memory medium reader, etc.

The present invention also provides an information processing device that permits internal mounting of a relevant device, comprising;

a cooling fan having variable rotation speeds, temperature obtaining means for obtaining a temperature within the information processing device, attaching-detaching state obtaining means for obtaining an attaching-detaching state of the relevant device, control means for controlling the rotation speed of the cooling fan, and reference data that shows the relationship between a value relative to the rotation speed of the cooling fan and the temperature and is determined depending upon attaching-detaching state of the relevant device,

wherein said control means determines the reference data to be referred to, on the basis of the attaching-detaching state of the relevant device obtained by the attaching-detaching state obtaining means, calculates the value relative to the rotation speed of the cooling fan from the temperature obtained by the temperature obtaining means and said reference data, and controls the rotation speed of the cooling fan on the basis of the obtained value.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory view showing the shapes of three constructional members of a box body <b>100</b> of an entertainment apparatus in one embodiment of the present invention.

FIG. 2 is a perspective view showing a state in which an upper box body is removed from the box body <b>100</b> of the entertainment apparatus in one embodiment of the present invention.

FIG. 3 is a perspective view showing a rear face of the box body <b>100</b> of the entertainment apparatus in one embodiment of the present invention.

FIG. 4 is a cross-sectional view showing the entire construction of the entertainment apparatus in one embodiment of the present invention.

FIG. 5 is a perspective view showing a state in which an intermediate plate is removed from the box body <b>100</b> of the entertainment apparatus in one embodiment of the present invention.

FIG. 6 is a side view of a main board <b>381</b>.

FIG. 7 is a schematic view of layout of main parts of a main substrate <b>381</b><i>a. </i>

FIG. 8 is a schematic view of layout of main parts of a power substrate <b>381</b><i>b. </i>

FIG. 9 is a schematic view of a correspondence table for fan control as one example of data for use in the control of a cooling fan.

FIG. 10 is a flow chart for explaining a processing flow of a microcontroller <b>411</b>.

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will be explained with regard to a case of application of the present invention to an entertainment apparatus as an information processing device with reference to the drawings. While the present invention is not limited to the entertainment apparatus, the present invention is more effective when applied to a device that is limited in appearance, size, parts to be used, etc. to a certain extent as in the entertainment apparatus for wide popularization thereof.

A box body <b>100</b> of the entertainment apparatus in this embodiment is constituted of three portions as shown in FIG. <b>1</b>. Namely, the box body <b>100</b> is constituted of an upper box body <b>110</b>, a central chassis <b>140</b> and a lower box body <b>170</b>. Each of the upper box body <b>110</b> and the lower box body <b>170</b> generally has a flat rectangular parallelepiped shape. The upper box body <b>110</b>, the central chassis <b>140</b> and the lower box body <b>170</b> are fixed and integrated with bolts that are not shown.

The central chassis <b>140</b> has a rear face portion <b>141</b> and an intermediate plate <b>142</b>. This intermediate plate <b>142</b> partitions a space within the box body <b>100</b> into a storing space on the upper box body <b>110</b> side and a storing space on the lower box body <b>170</b> side. This intermediate plate <b>142</b> has, mounted thereon, various kinds of devices stored into the upper box body <b>110</b>. Examples of the devices mounted on the intermediate plate <b>142</b> include a disk unit <b>310</b>, a slot unit <b>301</b>, a power unit <b>302</b> and a switch-inlet unit <b>304</b> as shown in FIG. 2. A through hole <b>142</b><i>b </i>and a through hole <b>142</b><i>c </i>are also made in the intermediate plate <b>142</b> (see FIG. <b>1</b>). A hood <b>142</b><i>d </i>is arranged in the intermediate plate <b>142</b> so as to cover the through hole <b>142</b><i>b</i>. A radiation fin <b>306</b> (see FIG. 2) arranged in the lower box body <b>170</b> extends through the through hole <b>142</b><i>b</i>, and is stored into the hood <b>142</b><i>d</i>. A notch portion <b>142</b><i>a </i>is formed in the intermediate plate <b>142</b> and a cooling fan <b>305</b> is arranged in the intermediate plate <b>142</b>. The slot unit <b>301</b> is fastened to a projection arranged on an upper face of the intermediate plate <b>142</b> with a screw so that the slot unit <b>301</b> is fixed to the intermediate plate <b>142</b>.

The disk unit <b>310</b> is a recording medium drive unit for reproducing a disk type recording medium such as CD, DVD, etc., and has a tray (not shown) capable of sliding in and out. The disk type recording medium is to be mounted on the tray. A reproduction portion for storing the tray to reproduce the disk such as CD, DVD, etc. mounted on the tray is built in the disk unit <b>310</b>.

As shown in FIG. 3, a notch portion <b>143</b><i>a </i>is formed in the rear face portion <b>141</b> of the central chassis <b>140</b>. The switch-inlet unit <b>304</b> is exposed from the notch portion <b>143</b><i>a </i>to the exterior. An exhaust port <b>143</b><i>b </i>is formed in a position where the rear face portion <b>141</b> faces the cooling fan <b>305</b>. In addition thereto, as shown in FIG. 3, various kinds of communication terminals <b>521</b>, <b>522</b> are arranged in a lower rear face member <b>144</b>. An opening portion <b>523</b> as an insertion port of an external memory device of an attaching-detaching type is made in the rear face portion <b>141</b>. In a normal using state, the opening portion <b>523</b> is covered with a cover that is not shown.

As shown in FIG. 4, a main board <b>381</b> having a central processing unit <b>401</b> mounted thereon is arranged in the lower box body <b>170</b>. Further, as shown in FIG. 5, a storing case <b>391</b> of the external memory device of the attaching-detaching type and a ventilation port <b>190</b> are arranged in the lower box body <b>170</b> together with the main board <b>381</b>.

As shown in FIG. 6, the main board <b>381</b> has a two-layered structure constituted of a main substrate <b>381</b><i>a </i>and a substrate <b>381</b><i>b </i>for power. A heat sink <b>307</b> integrated with the radiation fin <b>306</b> and a shield <b>308</b> formed of a metallic plate are arranged between the two substrates. Required circuits can be efficiently stored in a limited space by forming the above two-layer structure in which the heat sink and the shield are sandwiched between the substrates.

As shown in FIG. 7, the central processing unit <b>401</b>, a main memory device <b>402</b> and a drawing processor <b>403</b> are arranged as main parts in the main substrate <b>381</b><i>a</i>. A temperature sensor <b>404</b> is also arranged in the vicinity of the central processing unit <b>401</b>. Further, a connector portion <b>405</b> to be used for electric connection with the power substrate <b>381</b><i>b </i>and a signal line cable <b>406</b> to work as a signal path of data when the external memory device is mounted are further arranged on the main substrate <b>381</b><i>a. </i>

Heat is generated by operation of the central processing unit <b>401</b>, etc. arranged on the main substrate <b>381</b><i>a</i>. This heat is conducted to the heat sink <b>307</b> and is further conducted to the radiation fin <b>306</b>. The air taken-in from the ventilation port <b>190</b> passes between respective fins of the radiation fin <b>306</b> when the air flows toward the cooling fan <b>305</b>, whereby the air absorbs heat from the radiation fin <b>306</b>. The air is exhausted from the cooling fan <b>305</b> to the exterior.

As shown in FIG. 8, the power substrate <b>381</b><i>b </i>is provided with a microcontroller <b>411</b> for controlling a voltage supplied to each device within the entertainment apparatus, a connector portion <b>412</b> to be used for electric connection with the main substrate <b>381</b><i>a</i>, an external memory device power line <b>413</b> for supplying the voltage when the external memory device is mounted, and a cooling fan power line <b>414</b> for supplying the voltage to the cooling fan <b>305</b>. The microcontroller <b>411</b> can determine whether or not the external memory device is mounted by monitoring a state of the power line <b>413</b> of the external memory device. Further, the microcontroller <b>411</b> can obtain a temperature measured by the temperature sensor <b>404</b> through the connector portion <b>405</b> of the main substrate <b>381</b><i>a </i>and the connector portion <b>412</b> of the power substrate <b>381</b><i>b. </i>

A general-purpose hard disk drive unit can be used as the external memory device to be mounted on this entertainment apparatus. The hard disk drive unit has a power connector portion and a data line connector portion. The external memory device power line <b>413</b> from the entertainment apparatus is connected to the power connector portion, and the signal line cable <b>406</b> is connected to the data line connector portion, so that the external memory device attains an operable state. The external memory device can then transmit and receive data in accordance with commands from the entertainment apparatus.

At this time, the external memory device can be stored to a storing case <b>391</b>, and attains a fixing state by closing a cover, so that the external memory device is stored in the entertainment apparatus.

Control of the cooling fan in the entertainment apparatus of the above construction will be explained below.

In this embodiment, the microcontroller <b>411</b> has a correspondence table for the fan control as data to be used for the control of the cooling fan, for example, as schematically shown in FIG. <b>9</b>. There may be employed a constitution in which the data to be used for the fan control is stored in the exterior of the microcontroller <b>411</b> and is referred to by the microcontroller <b>411</b>. A format and values of the data to be used for the fan control are not limited to the example of this Figure. For example, a table format, a program format, etc., may be employed.

In the correspondence table for the fan control in this Figure, the axis of ordinate shows the value of a voltage supplied to the cooling fan <b>305</b>, and the axis of abscissa shows the temperature measured by the temperature sensor <b>404</b> arranged in the vicinity of the central processing unit <b>401</b>. This table shows the relationship between a temperature range and the supplied voltage when the external memory device is mounted (a graph shown by a broken line) or not mounted (a graph shown by a solid line). The above temperature range applied with respect to a certain supplied voltage is called a temperature zone. A plurality of temperature zones are set for each of the time periods when the external memory device is mounted and not mounted.

Namely, when a certain temperature zone corresponding to the measured temperature is applied, and when the temperature rises and exceeds an upper limit of the present temperature zone, the present temperature zone is changed to a temperature zone for increasing the supplied voltage to the cooling fan <b>305</b>, to increase the rotation number of the cooling fan <b>305</b>. Conversely, when the temperature decreases to be lower than a lower limit of the present temperature zone, the present temperature zone is changed to a temperature zone for decreasing the supplied voltage to the cooling fan <b>305</b>, to decrease the rotation number of the cooling fan <b>305</b>. The voltage corresponding to the measured temperature can be accordingly supplied to the cooling fan <b>305</b>.

As can be seen from this Figure, when the temperatures are at the same level, the microcontroller <b>411</b> supplies a higher voltage to the cooling fan <b>305</b> when the external memory device is mounted than when the external memory device is not mounted (provided that the case of supplying a highest voltage is excluded). That is because it is considered that heat sources and cooling objects are increased in number and the passage of a cooling air current becomes worse by mounting the external memory device. Further, that is because the influence of a noise generated by the cooling fan comes to be relatively low even when an increase in the rotation number makes the increased fan noise since the external memory device generates a noise.

Adjacent temperature zones are respectively set so as to overlap by 0.5° C., so that so-called hysteresis characteristics are provided. Thus, a frequent change from one temperature zone to another is prevented when the measured temperature is close to a boundary of each temperature zone.

Further, a limit value of the temperature (74° C. in the example of this Figure) is set, and when the measured temperature reaches the limit temperature, the microcontroller <b>411</b> stops supply of the voltage to the central processing unit <b>401</b> and the drawing processor <b>403</b>.

The control of the cooling fan <b>305</b> in the above constitution will be explained. FIG. 10 is a flow chart for explaining processing by the microcontroller <b>411</b> in this case.

When the entertainment apparatus is started, the microcontroller <b>411</b> determines whether or not the external memory device is mounted from a state of the power line <b>413</b> of the external memory device. When the microcontroller <b>411</b> determines that the external memory device is mounted, the microcontroller <b>411</b> refers to the graph applied when the external memory device is mounted. When the microcontroller <b>411</b> determines that no external memory device is mounted, the microcontroller <b>411</b> refers to the graph applied when the external memory device is not mounted (S<b>101</b>).

Then, the microcontroller <b>411</b> initializes the temperature zone (S<b>102</b>). In this example, the temperature zone is set to a lowest range of the applied temperature in the initialization. The microcontroller <b>411</b> then supplies the cooling fan <b>305</b> with a voltage corresponding to this temperature zone.

The value of a variable N as a counter is then set to zero (S<b>103</b>). The above counter is used to count the number of times of the measured temperature serially exceeding the present temperature zone range. This aims at changing one temperature zone to another when the measured temperature exceeds the present temperature zone in serial three temperature measurements by taking account of a case where noises, etc., cause a large error on the measured temperature. Two variables of the counter may be also used on upper and lower limit sides of the temperature zone.

Then, the microcontroller <b>411</b> obtains the temperature measured by the temperature sensor <b>404</b> near the central processing unit <b>401</b> (S<b>104</b>). The microcontroller <b>411</b> then referrs to the correspondece table for the fan control, to determine whether or not the temperature reaches a limit value (S<b>105</b>). When the temperature reaches the limit value, the microcontroller <b>411</b> terminates the supply of the voltage to the central processing unit <b>401</b> and the drawing processor <b>403</b> (S<b>106</b>). When this temperature does not reach the limit value, the microcontroller <b>411</b> refers to the correspondence table for the fan control, to determine whether or not the obtained temperature is outside the range of the present temperature zone (S<b>107</b>).

When no obtained temperature is outside the range of the present temperature zone, i.e., when the obtained temperature is within the range of the present temperature zone, the value of the variable N is reset to zero (S<b>108</b>). The microcontroller <b>411</b> then determines whether the external memory device is attached or detached from the state of the power line <b>413</b> of the external memory device (S<b>113</b>).

When the obtained temperature is outside the range of the present temperature zone, the value of N is increased by one (S<b>109</b>). The microcontroller <b>411</b> then determines whether or not the value of N comes to be 3 (S<b>110</b>). If the value of N is not 3, the microcontroller <b>411</b> does not change the temperature zone and determines the attachment-detachment of the external memory device since it determines that no change of temperature zones serially takes three times (S<b>113</b>). When the value of N is 3, the temperature zone is changed to another since it determines that the obtained temperature comes to be outside the range of the present temperature zone serially three times (S<b>111</b>). In this case, when the obtained temperature is lower than the lower limit of the present temperature zone by referring to the correspondence table for the fan control, the microcontroller <b>411</b> changes the temperature zone to another temperature zone for increasing the voltage supplied to the cooling fan <b>305</b>. When the obtained temperature is higher than the upper limit of the present temperature zone, the microcontroller <b>411</b> changes the temperature zone to another temperature zone for decreasing the voltage supplied to the cooling fan <b>305</b>. Then, the value of the variable N is reset to zero (S<b>112</b>).

As described above, in the determination of attaching-detaching (S<b>113</b>) of the external memory device, the microcontroller <b>411</b> checks the state of the power line <b>413</b> of the external memory device, to determine whether or not there is a change in the attachment-detachment of the external memory device. As a result, when there is a change in the attachment-detachment, the process returns to the processing in S<b>102</b>, and the referred graph is changed to another, and the present temperature zone is set to that in an initial state when the external memory device is attached or detached. On the other hand, when there is no change in the attachment-detachment, the process returns to the processing in S<b>104</b>, and the temperature is obtained. The determination of attaching-detaching of the external memory device may be made separately from the processing shown in the flow chart of this Figure, and initialization processing (S<b>102</b>) of the temperature zone may be performed by interruption when there is a change in the attachment-detachment.

While there may be employed any cycle time of the above series of processings for obtaining the temperature and determining the change in the temperature zone, it can be set to, e.g., a predetermined period (250 m seconds, one second, etc.).

While the above example explains an embodiment in which the supplied voltage corresponds to the temperature zone, there may be employed an embodiment in which, for example, the temperature and the supplied voltage correspond to each other. This embodiment does not require the counter measurement or the determination of the change in the temperature zone, etc., so that the processing of the microcontroller <b>411</b> can be simplified.

In accordance with the present invention, therefore, therefore, it is possible to perform suitable control of the cooling fan depending upon the attaching and detaching states of the external memory device, etc. in the information processing device that permits internal mounting of the external memory device, etc.